This invention relates to apparatus and methods of imprinting identifying characters on the end face of metal bar stock. More precisely, this invention relates to the imprinting of identifying characters on the end face of bolt blanks.
As a safety measure, the American Society for Testing and Materials (ASTM) requires as a part of its standard that all bolts, stud and headed, carry identifying characters in order to identify the bolt manufacturer in the event of bolt failure. This requirement is part of the ASTM designation A193. Accordingly, all bolts manufactured to ASTM standards must carry the identifying characters. For headed bolts the characters can be imprinted in the head forging process, but in the manufacture of stud bolts, the characters have to be separately imprinted. Various methods are used to imprint the identifying characters. The characters can be hand stamped but this is slow and costly because of the labor involved. Some machines have been designed to take bolt blanks and impress the identifying characters on the bolt blanks in a separate operation. This is also costly, since a separate machine is needed to handle the bolt blanks and to stamp the characters thereon. Also involved is additional labor in operating a separate machine, loading and unloading the machine with bolt blanks prior to further processing.
Accordingly, one primary feature of the present invention is to provide means for impressing identifying characters on the end face of bolt blank bar stock before the bolt blank has been cut, thereby eliminating the need for a separate stamping operation.
Another feature of the present invention is to provide a method of impressing identifying characters on the end face of bolt blank bar stock prior to cutting the bolt blank that does not interfere with the cutting operation.